GB2519134A

GB2519134A - A method of manufacturing a three-dimensional article

Info

Publication number: GB2519134A
Application number: GB1318028.6A
Authority: GB
Inventors: Giles Henry Rodway
Original assignee: Spinetic Energy Ltd
Current assignee: Spinetic Energy Ltd
Priority date: 2013-10-11
Filing date: 2013-10-11
Publication date: 2015-04-15
Also published as: GB201318028D0

Abstract

A method of manufacturing a three dimensional article comprising forming an object using a 3D printing method with at least one cavity 8 and filling the cavity 8 with a filler material (10 fig 4), increasing the rigidity of the object. The method may comprise generating a computer model of the article and modifying the model to introduce the cavity 8 in the article which would have otherwise been solid. This may be performed by a computer implemented algorithm. The object may be a hollow shell with walls defining the outer surface of the 3d article. One or more structural supports may be provided in the cavity 8. The volume of the cavity 8 may be greater than the volume of 3d printed material. The filler (10 fig 4) may be a thermosetting resin or an inorganic material. The filler (10 fig 4) may be cement or plaster. The filler (10 fig 4) may be a solid material which is introduced into the cavity 8. The filler (10 fig 4) may be provided in sheet form. The method may comprise encapsulating the filler (10 fig 4) by 3d printing. This can increase the production speed and reduce the costs.

Description

A METHOD OF MANUFACTURING A THREE-DIMENSIONAL ARTICLE

The invention relates to a method of manufacturing a three-dimensional article which incorporates a 3D printing method.

Three-dimensional (3D) printing (also sometimes referred to as additive manufacturing) allows three-dimensional objects of virtually any shape to be formed quickly and economically. Accordingly, 3D printing is becoming increasingly popular as a method for prototyping new products.

3D printing is achieved using an additive process, whereby successive layers of material of differing shape are laid down to form the object. A digital model of the object can be sliced into a series of layers which are then recreated by the printer using

a suitable material.

Several 3D printing techniques are known which deposit layers of material in different ways. Fused deposition modeling is a popular 3D printing technique which typically uses a thermoplastic filament. The filament is fed to an extrusion nozzle which heats and melts the material. The extrusion nozzle (or a movable table) can be moved in three dimensions to deposit the material as required to form the layers of the object.

The thermoplastic material hardens after being extruded from the nozzle to form a solid object.

Although 3D printing techniques are relatively fast and economical, large, solid objects can take considerable time to form and require a significant amount of thermoplastic filament (or other media).

The present invention seeks to provide a method of manufacturing which alleviates these problems and can form relatively large, solid objects more quickly and at lower cost.

In accordance with an aspect of the invention there is provided a method of manufacturing a three-dimensional article, the method comprising: forming an object using a 3D printing method, the object corresponding to the three-dimensional article but having at least one hollow and open cavity; and tilling the cavity of the object with a filler material so as to increase the rigidity of the object and to form the three-dimensional article.

The method minimises the amount of material which is 3D printed, whilst still producing an article having sufficient structural rigidity.

The method may further comprise: generating a computer model of the three-dimensional article; and modifying the computer model so as to produce a computer model of the object to be formed by introducing the at least one cavity in a section of the article which would otherwise have been solid.

Modifying the computer model may be performed by a computer-implemented algorithm.

The object to be formed may be a hollow shell having walls which define the outer surfaces of the three-dimensional article.

One or more structural supports may be provided within the at least one cavity. Such supports may be configured to withstand lateral loading, particularly before the cavity is filled with the filler material.

A volume of the at least one cavity may be greater than a volume of 3D printed material.

The filler material may be a thermosetting resin.

Alternatively, the filler material may be an inorganic material, such as cement or plaster.

The filler material may be a solid material which is introduced into the at least one cavity, for example, in sheet form.

The method may further comprise encapsulating the filler material by 3D printing.

The invention also extends to a three-dimensional article formed using such a method.

For a better understanding of the present disclosure, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:-Figure 1 is a flowchart of a method of manufacturing according to an embodiment of the invention; Figure 2 is a computer model showing a perspective view of an article to be manufactured; Figure 3 is a computer model showing a perspective view of a hollow shell for 3D printing; Figure 4 is a perspective view of the finished article; and Figure 5 is a perspective view of an alternative filling step.

A method of manufacturing according to an embodiment of the invention will be described with reference to the flowchart of Figure 1 and the representative illustrations of Figures 2 to 4.

In a first step (Si) of the method of manufacturing, a computer model of an article to be manufactured is generated. The computer model is generated using known techniques in a suitable CAD or CAM software package.

In the representative illustration of Figure 2, the article is an I-beam 2 which comprises a pair of flanges 4 and an adjoining web 6. Although in some contexts the I-beam 2 exists as a computer model and in others as a physical object, the same reference numerals will be used throughout.

The computer model is then modified by introducing at least one hollow and open cavity in a section of the article which would otherwise have been solid (S2).

This may be achieved by analyzing the computer model of the article to be manufactured to identify sections of the article in which solid material can be removed to form the at least one cavity. This can be performed manually or using a suitable algorithm or software module.

Figure 3 shows an example where the whole of the 11-beam 2 is hollowed out to form a single open cavity 8. Accordingly, the computer model represents only the outer surfaces of the I-beam 2 with an upper surface having been removed. In effect, the modified computer model is a hollow shell of the article to be manufactured.

A conventional 3D printing technique, such as fused deposition modeling, can then be used to form the hollow shell to the specification of the computer model (S3). The hollow shell may be formed from a thermoplastic resin such as polylactic acid (PLA).

Once fully formed, a filler material 10 can be introduced into the cavity 8 to replace the material removed from the computer model (S4).

As shown in Figure 4, the filler material 10 fills the cavity 8 and forms the upper surface of the I-beam 2. With the filler material 10 in place, the article corresponds to the computer model of the article initially generated.

The filler material 10 is a thermosetting resin such as epoxy, polyester, or phenolic.

The filler material 10 may also be provided with reinforcing fibres such as glass fibre (e.g. mat or chopped strand), carbon fibre, metal fibres, and/or particulate fillers such as fumed silica, glass microspheres, talc, titanium dioxide, ceramic beads, sand, etc. The filler material 10 is introduced into the cavity 8 in liquid form and is then cured by heating and/or using suitable radiation (such as UV light).

The 3D printed shell forms an integral part of the finished article, with the outer surfaces of the shell defining the outer surfaces of the finished article.

An article manufactured using the method of the present invention is both cheaper and quicker to manufacture than a solid article manutactured solely using 3D printing.

Accordingly, the method of the present invention is particularly well suited to forming prototypes or other items which are expected to have a relatively short usage. Further, the cured filler material 10 provides rigidity to the hollow shell and can result in an article which is as strong or even stronger than the equivalent 3D-printed article.

Although the filler material 10 has been described as being a thermosetting resin, other suitable materials may be used. For example, inorganic materials such as cement or plaster could be used in place of resin. It may also be possible to use thermoplastic resins and low melting point metals, though these would of course be problematic for low melting point 3D printing materials such as PLA.

In addition, the filler material may be solid when introduced into the cavity 8. For example, sheets of material, such as glass fibre mat, may be slotted into the cavity 8, as shown in Figure 5. With this arrangement large, solid objects, such as metal strips or plates, may be introduced into the cavity and then encapsulated in resin which may be 3D-printed on top thereof.

The cavity 8 need not be entirely hollow and structural members may be provided in the cavity 8 to support the walls of the shell. For example, supporting struts may extend between opposing walls of the shell which are then surrounded by the filler material 10. For example, in the illustrated example, a strut may be provided between the opposing walls of the flanges 4 across the web 6.

Moreover, the cavity 8 need not be open over its full area provided a sufficient opening is left to allow the filler material 10 to be introduced and, if required, properly cured.

Although the embodiment described herein has a single cavity 8, it will be appreciated that several discrete cavities may be used which can be individually filled with filler material.

Preterably, where two or more discrete cavities are provided, the openings to those cavities are oriented in the same direction to allow the filler material to be introduced and cured in a single process. However, the filling process could be performed in several steps to allow more complicated arrangements of cavities to be used.

Although the invention has been described with respect to 3D printing of polymers, it may also be extended to 3D printing of metals, using a technique such as Direct Metal Laser Sintering (DMLS). For example, a titanium shell may be produced using DMSL and then filled with molten steel, or an aluminium shell may be produced using DMSL and then filled with molten zinc. Such a technique can produce a complex article without the need for a mould and much quicker than 3D printing the entire solid object.

Moreover, the material of the shell can be selected so as to provide a corrosion resistant exterior to the article, without unnecessarily increasing costs.

The embodiment described herein is purely illustrative and it will be appreciated that articles of any design could be formed using the method of the invention.

Claims

CLAIMS1. A method of manufacturing a three-dimensional article, the method comprising: forming an object using a 3D printing method, the object corresponding to the three-dimensional article but having at least one hollow and open cavity; and tilling the cavity of the object with a filler material so as to increase the rigidity of the object and to form the three-dimensional article.
2. A method of manufacturing as claimed in claim 1, wherein the method further comprises: generating a computer model of the three-dimensional article; and modifying the computer model so as to produce a computer model of the object to be formed by introducing the at least one cavity in a section of the article which
3. A method of manufacturing as claimed in claim 2, wherein modifying the computer model is performed by a computer-implemented algorithm.
4. A method of manufacturing as claimed in any preceding claim, wherein the object to be formed is a hollow shell having walls which define the outer surfaces of the three-dimensional article.
5. A method of manufacturing as claimed in any preceding claim, wherein one or more structural supports are provided within the at least one cavity.
6. A method of manufacturing as claimed in any preceding claim, wherein a volume of the at least one cavity is greater than a volume of 3D printed material.
7. A method of manufacturing as claimed in any preceding claim, wherein the filler material is a thermosetting resin.
8. A method of manufacturing as claimed in any of claims 1 to 6, wherein the filler material is an inorganic material.
9. A method of manufacturing as claimed in claim 8, wherein the filler material is cement or plaster.
10. A method of manufacturing as claimed in any preceding claim, wherein the filler material is a solid material which is introduced into the at least one cavity.
11. A method of manufacturing as claimed in claim 10, wherein the filler material is provided in sheet form.
12. A method of manufacturing as claimed in claim 10 or 11, further comprising encapsulating the fillei material by 3D punting.
13. A method of manufacturing a three-dimensional article substantially as described heiein with ieference to and as shown in the accompanying diawings.
14. A three-dimensional article formed using a method as claimed in any preceding claim.